Why does CT utilise compton scattering?

[lavster]

why does conventional xray imaging utilise photoelectric effect but ct utilise compton scattering? i know that at different energies, different mechanisms (eg compton scattering, photoeletric effect, pair production) dominate but do they not chose the energy beam to correspond the process that they want - i know they harden the beam (ie get rid of low energy photons) for example

cheers

 

[mathman]

The point you are making is correct. Compton scattering is the dominant process for higher energy (~ 1 Mev or high kev) for photons.